Closure locking device



United States Patent [56] References Cited UNITED STATES PATENTS 2,250,736 7/194] [72] inventor Norman E. Lauterbach Pittsford, New York [211 App]. No. 761,905

Torresen 2,468,193 4/1949 Goff.......... 2,966,247 12/1960 Bryer... 3,442,360 5/1969 F [22] Filed Sept. 24, 1968 [4S] Patented Nov. 10, 1970 [73] Assignee Ritter Pfaudler Corporation Rochester, New York ulop FOREIGN PATENTS 786,899 11/1957 Great Britain................ Primary Examiner-Marvin A. Champion Assistant Examiner-Edward J. McC Attorney-Theodore B. Roessel arthy a corporation of New York Patented Nov. 10, 1970 Sheet O 3 3 O 8 6 o 4 2 3 4 2 2 w 2 8 6 5 4 m 4 3 2 m 5 6 4 6 6 6 86/ 1 5 J H m fi P q 2 MW 6 M & BF, Lu I. O B W. m f/ 2 FIG. 1

ATTORNEY Patentd Nov. 10, 1970 Sheet -F|G. 3 E

2 INVENTOR NORMAN E. LAUTERBACH ATTORNEY CLOSURE LOCKING DEVICE BACKGROUND OF THE INVENTION This invention relates generally to a closure locking device, and more particularly to a slip clutch mechanism for locking the door ofa sterilizer chamber.

In medical sterilizers, the problem of overtightening of the gasket seal by the closed door is ever present. The prior art door closures consist ofa threaded stud fixed to the central portion of the door and locking means which are rotated around the threaded stud by means ofa hand wheel to position the door and door seal against the margins of the sterilizer chamber. With such locking means, it is often difficult, if not impossible, to obtain a predetermined pressure on the door seals in order to achieve proper sealing and yet not damage the door seal by overtightening of the door.

SUMMARY OF THE INVENTION The present invention overcomes the difficulties and limitations found in prior art locking devices and provides a sterilizcr door closure mechanism that is designed to prevent overtightcning of the door seal and thereby minimize any subsequent damage to the seal proper.

In order to achieve this, the present invention utilizes force limiting means which are interposed between the locking means of the door and the hand wheel for locking the door to limit the door closing force to a predetermined magnitude. The force limiting means comprises a releasable cup member which is resiliently held in a torque transmitting relationship with the door handle and is designed to disengage. thereby rendering the door immovable whenever a predetermined closing force is obtained.

Accordingly, it is an object of the invention to provide a new and novel door closure which is designed to prevent over.- tightening of the door seals and any subsequent damage to the door seal.

Another object of the invention is to provide a new and novel door closure mechanism which'allows the door to be consistently closed against the door seal with a predetermined force, thereby consistently effecting the door seal without overtightening of the seal.

Still another object of the invention is to provide a new and novel door closure mechanism whereby the operator in order to close the door will be required to expend only predetermined amounts ofenergy to obtain a proper seal,

These and other objects, advantages of the invention will become apparent from a study of the attached drawings and from a reading ofa description of the preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross-sectional view of the invention showing the location ofthc parts generally;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. I; and

FIG. 3 is a partial sectional view taken along line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring more particularly to the drawings, there is shown generally at the door closure mechanism and comprises a door 12 having a threaded stud l4 rigidly mounted in the central portion thereof. The door 12 contains a seal 16 fixed on the outer portion of the door by well known means. The seal 16 is designed to engage the margins l8 of the sterilizer chamber 20.

Rotatably mounted on the threaded stud I4 is an internally threaded cylindrical member 22 containing a flange 24 formed between the ends thereof. The flange 24 contains a plurality of engaging members 26 in the form of pan-head screws shown in the embodiment of FIGS. I and 2.

Also rotatably mounted on one end of the cylindrical member 22 is a first plate member 28 in the form of a spider having a plurality of rearwardly extending arms 30. Rigidly fastened to the arms 30, by a plurality ot'scrcws 32, are means 34 for rotating the first plate member 28 fixedly attached thereto. The rotating means 34 may take the form ofa hand wheel as shown in FIG. 1 or may be some other suitable rotating means.

Surrounding the flange 24 formed on the cylindrical member 22 is a cup member 36 which is mounted, by well known means, for rotation around the cylindrical member 22. The cup member 36 is also mounted, by well known means, for movement longitudinally from a driving or force transmitting position to a nondriving position, as will be hereinafter described. Thecup member 36 contains a plurality of holes 38 formed in the bottom thereof at a distance from the axis of the threaded stud I4 sufficient to engage the engaging members 26.

Formed on the side of the cup member 36 are a plurality of cam surfaces 40 in the form ofa slot shown in FIG. 3. The first plate member 28 contains a plurality of cam followers 42 in the form ofa shoulder screw in the embodiment shown in FIG.

I. The cam followers 42 are fixed on the outer end of the first plate member 28 and are associated with the cam surface 40 to impart a longitudinal motion to the cup member 36 to move the cup member 36 from the driving position to the nondriving position, as will be hereinafter described.

A spring bias means 44. shown in FIG. 2, is attached to the cam followers 42 by means of a spring retainer clip 46 at one end and to the cup member 36 by means of the pin 48 at the other end thereof. The bias means 44 is designed to rotate the cup member 36 whenever insufficient relative motion occurs 7 between the cup member 36 and the cam followers 42 to overcomethe bias of the bias means 44. When this occurs, as will be hereinafter described, the cam followers 42 impart a longitudinal motion to the cup member 36 by means of the cam surfaces 40, to move the cup member 36 from the driving position, shown in FIG. I, to the nondriving position.

Slidably mounted on the other end of the cylindrical member 22 is a second plate member 50 having a thrust bearing 52 fixed in the central portion thereof for association with the flange 24. In such a position, a longitudinal motion of the flange 24 is transmitted through the thrust bearing 52 to the second plate member 50.

The second plate member 50 contains a plurality of sockets formed around the outer edge thereof for receiving a plurality of balls 60. Associated with the sockets 54, in the second plate member 50, are a plurality of locking parts 56 which are formed from a plurality of locking bars 58 rigidly attached to the plurality of balls 60. A locking plate 62 is fixedly attached to the sccondplate member 50 by well known means and serves to retain theballs 60 of the locking parts 56 in the sockets 54 of the second plate member 50.

The locking bars 58 are designed to engage the margins 64 on the sterilizer chamber 20 and are pivotably mounted by means of the pivot mounting 66 which is rigidly attached to the door 12 of the sterilizer. When the locking parts 56 are pivotably mounted, as shown in FIG. 1, a longitudinal motion of the second plate member 50 causes the locking bar 58 to engage the margins 64 and move the door 12 into a locked position. In this locked position, the seal 16 is engaged in compression with the margins I8 on the sterilizer chamber 20 in a predetermined amount to seal the chamber from the outer atmosphere without over compressing the seal 16.

OPERATION In operation, the door 12 is pivoted towards a closed position by means not shown in the drawing and forming no part of this invention until the locking bars 58 are in proximity to the margin 64. A rotational movement of the rotating means 34 causes the first plate member 28 and the cam followers 42 to rotate. The cup member 36 is also caused to rotate by means of the bias means 44 fixedly attached thereto and to the cam followers 42.

When the cup member 36 is thusly rotated, the plurality of holes 38 engage the engaging members 26 and cause the flange 24 and the cylindrical member 22 to rotate and move inwardly. Since the cylindrical member 22 is threadably engaged with the threaded stud 14, a longitudinal movement of the cylindrical member 22 is translated into a longitudinal movement of the second plate member 50 by means of the thrust bearing 52. As a result, the locking parts 56, being pivotally mounted about the pivot mounting 66 engage the margins 64 with the locking bars 58. A continued longitudinal movement of the second plate member 50 causes the door 12 and seal 16 to engage the margins 18.

After the seal 16 has engaged the margins 18 and the seal 16 is being compressed to a predetermined amount, the longitudinal motion of the door 12, the second plate member 50 and the thrust bearing 52, being unable to freely move, imparts a resisting force to thc flange 24. This resisting force is then imparted to the cup member 36 by means of the engaging members 26 such that a continued rotation of the rotating means 34 will cause the cam followers 42 to engage the cam surface 40 and drive the cup member 36 to the nondriving position whenever the bias of the bias means 44 is overcome.

As a result, whenever the cup member 36 is in the nondriving position, the plurality of holes 38 will not engage the engaging members 26 and the rotating means 34 is free to rotate around the threaded stud 14 without driving the door 12 and seal 16 to a tighter closed position on the margins l8. By changing the bias of the bias means 44, the force exerted by the scal 16 against the margins 18 may be changed.

When it is desired to open the door 12, the operator simply reverses the rotation of the rotating means 34 thereby causing the cam follower 42 to engage the cam surface 40 in the reverse direction and drives the cup member 36 to the driving position shown in FIG. 1 to reverse the process and disengage the door 12 and the seal 16 from the margin 18.

From the above, it can be seen that there is provided a new and novel door closure mechanism whereby the door of a sterilizer may be moved into the locked position and sealed with a predetermined force. The predetermined force is determined by the bias of the bias means 44 which causes the cam followers 42 to impart a longitudinal motion to the cup member 36 to move the cup member 36 from the driving position, shown in FIG. 1, to the nondriving position. In this latter position,'the rotating means 34 is free to rotate without overtightening the seal 16 against the margin 18 and causing deterioration of the seal 16.

From the foregoing, it can be seen that new and novel door closure means have been provided for accomplishing all the objects and advantages of the invention. Nevertheless, it is apparent that many changes in the details ofconstruction and arrangement of parts may be made without departing from the spirit and scope of the invention, as expressed in the accompanying claims, and the invention is not to be limited to the exact manner shown and described, as only the preferred embodiments have been given by way of illustration.

lclaim:

1. A closure locking device adapted to apply a predetermined closing force to a closure member, comprising:

a. a threaded stud, rigidly mounted on the closure;

b. a cylindrical member, having a flange formed between the ends thereof, rotatably mounted on said stud;

c. a first plate member, rotatably mounted on one end of said cylindrical member;

d. means for rotating said first plate member, fixedly attached thereto;

a cup member surrounding said flange and said first plate member, rotatably and slidably mounted thereon, said cup member having:

I. at least one cam surface formed on the side thereof;

and

2. a plurality of holes formed in the bottom thereof;

f. at least one cam follower, fixed on the outer end of said first plate member and associated with said cam surface LII for impartinga longitudinal motion to said cup member to move said cup member from a driving position to a nondriving position;

g. a plurality ofengaging members, associated with said cup member, fixedly attached to said flange and positioned to engage said plurality of holes to rotate said flange whenever said cup member is in a driving position;

h. bias means, attached to said cam follower and to said cup member for rotating said cup member whenever insuffcient relative motion occurs between said cup member and said cam follower to overcome the bias of said bias means;

i. a second plate member, slidably mounted on the other end of said cylindrical member;

j. a thrust bearing fixed in the central portion ofsaid second plate member in association with said flange for transmitting the longitudinal movement of said flange to said second plate member; and

k. a plurality of locking parts associated with said closure and adapted to engage the margins of the opening associated with said closure so that a longitudinal motion of said second plate member causes said locking parts to move the closure into a locked position thereby preventing rotation of said flange and imparting a resisting force to said cup member sufficient to allow relative motion to occur between said cup member and said cam follower in predetermined amounts to overcome the bias of said bias means and cause said cam follower to imparta longitudinal motion to said cup member to move said cup member from a driving position to a nondriving position.

2. A closure locking device adapted to apply a predetermined closing force to a closure comprising:

a. a threaded stud rigidly mounted on said closure;

b. a cylindrical member threaded to said stud, said cylinder having a radial flange;

c. lock means for said closure including a plate slidably mounted on said member and a thrust bearing interposed between said plate and flange for moving said plate axially as said member rotates on said stud wherein axial movement of said plate moves said locking means to a closure locking position;

d. a radially extending member rotatably and slidably mounted on said cylinder, said radial member having a plurality of axial holes formed therein and being movable on said cylinder toward and away from said flange between a driving position and a nondriving position; engaging means fixed to said flange and extending axially therefrom into said holes when said radial member is in a driving position for rotating said cylinder and disengaged from said holes when said radial member is in a nondriving position;

f. drive means rotating said radial member for moving said plate and lock means to a closure locking position; and

g. means engaging the peripheral portion of said radial member for moving said member axially away from said flange to said nondriving position when said plate and lock means have been moved to a closure locking position.

3. A closure locking device as in claim 2 wherein said last mentioned means comprises:

a. a resilient element urging said drive means and radial member into a torque transmitting relationship;

b. a cam follower on said drive means; and

c. said radial member having a cam surface thereon associated with said cam follower, said cam surface being shaped to drive said radial member axially away from said flange against the urging of said resilient element to said nondriving position upon relative movement of said drive means and radial member.

4. A closure locking device as set forth in claim 3 wherein said radial member is cup-shaped with the wall thereof surrounding said flange, said holes being in the bottom of said cup-shaped member and cam surface being in the wall thereof.

6. A closure locking device as set forth in claim 5 whereir e number of said holes exceed the number of said pins. 

